JP2007113270A - Foundation structure and construction method of the foundation structure - Google Patents

Foundation structure and construction method of the foundation structure Download PDF

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JP2007113270A
JP2007113270A JP2005305774A JP2005305774A JP2007113270A JP 2007113270 A JP2007113270 A JP 2007113270A JP 2005305774 A JP2005305774 A JP 2005305774A JP 2005305774 A JP2005305774 A JP 2005305774A JP 2007113270 A JP2007113270 A JP 2007113270A
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pile
ground
steel pipe
tip
foundation
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JP4713297B2 (en
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Eiichiro Saeki
英一郎 佐伯
Makoto Nagata
誠 永田
Masatoshi Wada
昌敏 和田
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Nippon Steel Corp
Nippon Steel Engineering Co Ltd
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Nippon Steel Engineering Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a foundation structure capable of sufficiently ensuring bearing capacity to reduce cost and enlarging an applicable extent regardless of hardness of the ground and a construction method of the foundation structure. <P>SOLUTION: The ground near the front end of a pile is loosened after it has been confirmed that the front end of the pile of a steel pipe pile 2 is arrived to a bearing layer, and after then, load of an upper structure 4 is added to make the settlement of the steel pipe pile 2 by a loosening part to display bearing capacity RP1 of the front end of the pile and, at the same time, ground reaction force also acts to the bottom of a pressure resisting slab 3 making the settlement accompanied with the steel pipe pile 2 to obtain bearing capacity RS. Accordingly, bearing capacity of the front end of the pile is sufficiently ensured to enable bearing capacity (RP1+RP2+RS) of the whole foundation structure to rise, it can be also applied to a large scaled building 1 while contemplating the reduction of a cost without increasing a pile diameter or the number of piles. Further, the settlement of the steel pipe pile 2 is hard to occur after the display of the bearing capacity RP1, and differential settlement can be prevented even if a surface layer ground is weak. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、基礎構造および基礎構造の施工方法に関し、詳しくは、杭基礎と直接基礎とを併用して上部構造を支持する基礎構造、およびその施工方法に関する。   The present invention relates to a foundation structure and a construction method of the foundation structure, and more particularly to a foundation structure that supports an upper structure using a pile foundation and a direct foundation in combination, and a construction method thereof.

従来、杭基礎と直接基礎とを併用した基礎構造（パイルド・ラフト基礎）が知られている（例えば、特許文献１参照）。
パイルド・ラフト基礎は、杭先端が支持層まで達することなく支持力の小さな中間層で止めた杭基礎と、地盤表面に形成した直接基礎と、の両方の支持力によって上部構造の荷重を支持するものである。そして、杭先端を中間層で止めた杭が上部構造の鉛直荷重により若干量だけ沈下することで、直接基礎が地反力を受けるようになり、杭基礎および直接基礎の支持力と沈下量とが釣り合う状態において、杭基礎および直接基礎が分担して荷重を支持する基礎構造である。このようなパイルド・ラフト基礎では、杭基礎および直接基礎の両者で鉛直荷重を分担することで、杭基礎単独の基礎構造よりも杭本数や杭径等を節約してコストダウンを図ることができるとともに、地耐力が十分でなく直接基礎単独では荷重が支持できなかったり、沈下量が大きくなり過ぎたりするような地盤にも適用可能になるという長所を有している。 Conventionally, a foundation structure (a piled raft foundation) using a pile foundation and a direct foundation in combination is known (see, for example, Patent Document 1).
The piled raft foundation supports the load of the superstructure by the bearing force of both the pile foundation stopped by the intermediate layer with a small bearing capacity without reaching the support layer and the direct foundation formed on the ground surface. Is. Then, the pile with the pile tip stopped by an intermediate layer sinks by a small amount due to the vertical load of the superstructure, so that the direct foundation receives ground reaction force, and the bearing capacity and subsidence amount of the pile foundation and direct foundation Is a foundation structure in which the pile foundation and the direct foundation share the load and support the load. In such a piled raft foundation, by sharing the vertical load between the pile foundation and the direct foundation, the number of piles and the pile diameter can be saved and the cost can be reduced compared to the foundation structure of the pile foundation alone. At the same time, it has the advantage that it can be applied to ground where the ground strength is not sufficient and the load cannot be supported directly by the foundation alone, or the subsidence amount becomes too large.

特開２００２−１２９５８４号公報JP 2002-129484 A

しかしながら、前記特許文献１に記載されたような従来のパイルド・ラフト基礎においては、杭先端が支持力の小さな中間層で止まっているため、杭先端を支持層に貫入した場合の杭基礎と比較して杭の先端支持力が小さくなり、杭基礎の支持力と直接基礎の支持力とを合わせても十分に大きな支持力が確保できず、規模の小さな建物にしか適用できないという問題がある。そして、杭先端の支持力を確保するためには、杭径を大きくしたり、杭本数を増やしたりしなければならず、前述したようなコストダウンの効果が十分に得られないことになってしまう。
さらに、従来のパイルド・ラフト基礎では、杭先端が中間層で止まっているため、表層が軟弱な地盤に適用した場合には、直接基礎の沈下を杭によって制御することが難しく、不等沈下によって建物が傾斜してしまう可能性があり、地耐力が小さな軟弱地盤への適用が困難であるという問題もある。 However, in the conventional piled raft foundation as described in Patent Document 1, since the pile tip is stopped by an intermediate layer having a small supporting force, it is compared with the pile foundation when the pile tip penetrates into the supporting layer. As a result, the tip support force of the pile is reduced, and even if the support force of the pile foundation and the support force of the direct foundation are combined, a sufficiently large support force cannot be secured, and there is a problem that it can be applied only to small buildings. And in order to secure the bearing capacity of the pile tip, the pile diameter must be increased or the number of piles must be increased, and the cost reduction effect as described above cannot be obtained sufficiently. End up.
Furthermore, with the conventional piled raft foundation, the tip of the pile stops at the middle layer, so when applied to soft ground, it is difficult to control the settlement of the foundation directly with the pile. There is a possibility that the building may be inclined, and there is a problem that it is difficult to apply to soft ground with low earth bearing capacity.

本発明の目的は、支持力を十分に確保してコスト低減を図ることが可能で、地盤の硬軟に関わらずに適用範囲を拡大することができる基礎構造および基礎構造の施工方法を提供することにある。   An object of the present invention is to provide a foundation structure and a construction method of the foundation structure that can secure a sufficient supporting force and can reduce the cost, and can expand the application range regardless of the hardness of the ground. It is in.

本発明の請求項１に記載の基礎構造は、杭基礎と直接基礎とを併用して上部構造を支持する基礎構造であって、地盤に貫入される杭体と、地盤貫入後の杭体の杭頭部に連結されて地盤上に形成される底版部とを備え、前記杭体の杭先端が支持層に到達したことを確認してから当該杭先端近傍の地盤を緩めておくことで、上部構造の荷重により所定量だけ沈下して発揮される前記杭体による支持力と、この杭体に伴って沈下することで地反力を受けて発揮される前記底版部による支持力と、の両方の支持力によって前記上部構造の荷重を支持することを特徴とする。   The foundation structure according to claim 1 of the present invention is a foundation structure that supports an upper structure using a pile foundation and a direct foundation in combination, and a pile body that penetrates the ground, and a pile body that has penetrated the ground. It comprises a bottom plate part connected to the pile head and formed on the ground, and after confirming that the pile tip of the pile body has reached the support layer, by loosening the ground near the pile tip, A supporting force by the pile body that is exhibited by sinking by a predetermined amount due to a load of the superstructure, and a supporting force by the bottom plate part that is exerted by receiving a ground reaction force by sinking with the pile body The load of the superstructure is supported by both supporting forces.

以上の本発明によれば、杭先端が支持層に到達したことを確認した後に杭先端近傍の地盤を緩めておき、その後に上部構造の荷重が加わることで緩めた分だけ杭体が沈下して杭先端の支持力が発揮されるとともに、杭体の沈下に伴って沈下する底版部にも地反力が作用して支持力が得られ、これらの杭および底版部の両方の支持力で上部構造を支持することができる。従って、杭先端の支持力を十分に確保し、かつ直接基礎の支持力も得られるので、基礎構造全体の支持力を高めることができ、杭径や杭本数を増大させることなくコスト低減を図りつつ、規模の大きな（柱軸力が大きい）建物にも適用することが可能になる。
さらに、杭先端地盤を予め緩めた分だけ杭体が沈下して支持力が発揮されるので、この沈下した位置よりもさらに下方への杭体の沈下が生じにくく、表層地盤が軟弱な場合であっても不等沈下を防止することができる。従って、軟弱な地盤に対しても本発明の基礎構造が適用可能となり、杭基礎および直接基礎の併用基礎構造の適用範囲を拡大することができる。
ここで、杭体としては、場所打ちコンクリート杭でもよく、ＰＣ杭や鋼管杭等の既成杭でもよい。そして、杭体が既成杭の場合の施工方法としては、埋込み工法や打込み工法、回転・圧入工法、根固め工法など、適宜な工法が選択可能である。
また、底版部としては、杭頭部分に形成される独立フーチングで構成されてもよく、また基礎梁に沿った布基礎で構成されたものや、基礎底面を覆う耐圧版（ベタ基礎）で構成されたものでもよい。 According to the present invention described above, after confirming that the tip of the pile has reached the support layer, the ground near the tip of the pile is loosened, and then the pile body sinks by the amount loosened by applying the load of the superstructure. As a result, the support force at the tip of the pile is exerted, and the ground reaction force acts on the bottom plate part that sinks as the pile body sinks to obtain the support force. The superstructure can be supported. Therefore, it is possible to secure sufficient support force at the tip of the pile and to obtain the support force of the foundation directly, so that the support force of the entire foundation structure can be increased, while reducing costs without increasing the pile diameter and the number of piles. Therefore, it can be applied to a building having a large scale (large column axial force).
Furthermore, since the pile body sinks by the amount that the pile tip ground has been loosened in advance and the bearing capacity is exerted, it is difficult for the pile body to sink further downward than the sinked position, and the surface ground is soft. Even if it exists, unequal settlement can be prevented. Therefore, the foundation structure of the present invention can be applied to soft ground, and the application range of the combined foundation structure of the pile foundation and the direct foundation can be expanded.
Here, the pile body may be a cast-in-place concrete pile or an existing pile such as a PC pile or a steel pipe pile. And as a construction method in case a pile body is an existing pile, an appropriate construction method, such as an embedding method, a driving-in method, a rotation and press-in method, a rooting method, can be selected.
In addition, the bottom plate part may be composed of independent footings formed on the pile head part, or composed of a cloth foundation along the foundation beam, or a pressure plate (solid foundation) covering the foundation bottom. It may be done.

また、本発明の請求項２に記載の基礎構造は、請求項１に記載の基礎構造において、前記杭体は、回転により地盤に貫入される鋼管杭であって、この鋼管杭は、地盤貫入時のトルク値に基づいて杭先端が支持層に到達したことが確認された後に、貫入方向と逆方向に回転されて所定量だけ上方に引き上げられ、前記鋼管杭を引き上げることによって杭先端近傍の地盤が緩められることを特徴とする。
このような構成によれば、回転によって地盤に貫入される杭体を、杭先端が支持層に到達あるいは支持層に貫入したことを確認してから逆回転することで、容易に杭先端近傍の地盤を緩めることができる。さらに、逆回転の回転量を適宜調整することで杭体を引き上げる量が任意に設定でき、地盤を緩める程度、つまり上部構造の荷重による杭体の沈下量を適切に設定することができる。従って、杭基礎と直接基礎との負担支持力の割合が任意に設定可能となり、地盤の特性や上部構造の規模等に応じて基礎構造の設計の自由度を高めることができる。
ここで、地盤の支持層としては、地盤調査（ボーリング調査等）によって得られるＮ値が所定の値（例えば、Ｎ値５０）以上の地層であったり、せん断波速度が所定の値（例えば、４００m/s ）以上の地層であったりするが、このような支持層では、回転・圧入するための杭打ち機における駆動トルク値が急激に増大することにより、杭先端が支持層に到達したことが確認されるようになっている。 The foundation structure according to claim 2 of the present invention is the foundation structure according to claim 1, wherein the pile body is a steel pipe pile that is penetrated into the ground by rotation, and the steel pipe pile is After confirming that the pile tip has reached the support layer based on the torque value at the time, it is rotated in the direction opposite to the penetration direction and pulled upward by a predetermined amount. The ground is loosened.
According to such a configuration, the pile body penetrating into the ground by rotation can be easily rotated in the vicinity of the pile tip by rotating backward after confirming that the pile tip has reached the support layer or penetrated the support layer. The ground can be loosened. Furthermore, the amount of lifting the pile body can be arbitrarily set by appropriately adjusting the amount of reverse rotation, and the amount of settlement of the pile body due to the load of the superstructure can be appropriately set to the extent that the ground is loosened. Therefore, the ratio of the load bearing force between the pile foundation and the direct foundation can be arbitrarily set, and the degree of freedom in designing the foundation structure can be increased according to the characteristics of the ground, the scale of the upper structure, and the like.
Here, as the support layer of the ground, the N value obtained by the ground survey (boring survey etc.) is a ground layer having a predetermined value (for example, N value 50) or a shear wave velocity is a predetermined value (for example, 400m / s) or more, but in such a support layer, the driving torque value in the pile driving machine for rotating and press-fitting increased rapidly, and the pile tip reached the support layer. Has been confirmed.

この際、前記引き上げた後の鋼管杭の杭先端が前記支持層上面よりも上方に位置するようにしてもよく、また、前記鋼管杭は、杭先端が所定深さだけ支持層に貫入された後に引き上げられ、前記引き上げた後の鋼管杭の杭先端が前記支持層上面よりも下方に位置するようにしてもよい。
このような構成によれば、支持層近傍の地盤特性と必要とする杭先端支持力とに応じて、適宜杭先端位置を設定することで、合理的かつ経済的な基礎構造の設計および施工が可能になる。すなわち、さほど大きな先端支持力が必要とされない場合や、支持層直上の地盤がよい（Ｎ値が高い）場合などには、支持層上面よりも上方まで杭先端を引き上げ、比較的大きな先端支持力が必要な場合には、支持層上面よりも下方つまり杭先端を支持層に根入れするようにすればよい。従って、設計条件に応じて杭先端の位置を任意に選択することで、杭先端の支持力や沈下量を適切に設定することができ、設計や施工の合理化を図ることができる。 At this time, the pile tip of the steel pipe pile after the lifting may be positioned above the upper surface of the support layer, and the steel pipe pile is inserted into the support layer by a predetermined depth. The pile tip of the steel pipe pile that has been pulled up later and that has been pulled up may be located below the upper surface of the support layer.
According to such a configuration, a rational and economical foundation structure can be designed and constructed by appropriately setting the pile tip position according to the ground characteristics in the vicinity of the support layer and the required pile tip support force. It becomes possible. That is, when a large tip support force is not required, or when the ground just above the support layer is good (N value is high), the pile tip is pulled up above the support layer upper surface, and a relatively large tip support force is obtained. If it is necessary, the bottom of the support layer, that is, the tip of the pile may be embedded in the support layer. Therefore, by arbitrarily selecting the position of the tip of the pile according to the design conditions, it is possible to appropriately set the support force and the amount of settlement of the tip of the pile, and it is possible to rationalize the design and construction.

また、本発明の請求項５に記載の基礎構造は、請求項１に記載の基礎構造において、前記杭体は、杭先端に螺旋状あるいは複数の板からなる羽根を有して回転により地盤に貫入される鋼管杭であって、この鋼管杭は、地盤貫入時のトルク値に基づいて杭先端が支持層に到達したことが確認されるとともに、支持層確認後に、杭先端の深さ位置を維持したままで貫入方向および逆方向の少なくとも一方に回転され、前記鋼管杭の回転によって杭先端近傍の地盤が緩められることを特徴とする。
このような構成によれば、杭先端に螺旋状の羽根を有して回転によって地盤に貫入される杭体を、支持層に到達したことを確認してから杭の深さ位置を変えずに正回転や逆回転することで、螺旋状の羽根が同一深さ位置で空回りし、容易に杭先端近傍の地盤を緩めることができる。 Further, the foundation structure according to claim 5 of the present invention is the foundation structure according to claim 1, wherein the pile body has a spiral or blade made of a plurality of plates at the tip of the pile and is rotated to the ground. It is a steel pipe pile to be penetrated, and this steel pipe pile is confirmed that the pile tip has reached the support layer based on the torque value at the time of ground penetration, and the depth position of the pile tip is confirmed after the support layer check. While being maintained, it is rotated in at least one of the penetration direction and the reverse direction, and the ground near the tip of the pile is loosened by the rotation of the steel pipe pile.
According to such a configuration, a pile body that has a spiral blade at the tip of the pile and penetrates into the ground by rotation can be confirmed without changing the depth position of the pile after confirming that it has reached the support layer. By rotating forward or backward, the spiral blades are idle at the same depth position, and the ground near the pile tip can be easily loosened.

さらに、本発明の請求項６に記載の基礎構造は、請求項１から請求項５のいずれかに記載の基礎構造において、前記緩めた杭先端近傍の地盤が根固めされることを特徴とする。
このような構成によれば、緩めた杭先端近傍の地盤にセメントミルク等の根固め材を注入して根固めすることで、得られる先端支持力や沈下量を安定化させることができる。すなわち、根固めしない場合には、杭先端の羽根の形状等によって杭先端の沈下性状（沈下量や支持力等）が変動してしまう可能性があるのに対して、根固めすることで、羽根の形状等による杭先端条件の違いがなくなり安定した沈下性状を得ることができる。 Furthermore, the foundation structure according to claim 6 of the present invention is the foundation structure according to any one of claims 1 to 5, characterized in that the ground in the vicinity of the loosened pile tip is consolidated. .
According to such a configuration, it is possible to stabilize the obtained tip support force and the amount of settlement by injecting a root hardening material such as cement milk into the ground in the vicinity of the loosened pile tip and solidifying the root. In other words, when not rooting, the settlement characteristics (settlement amount, support force, etc.) of the pile tip may change depending on the shape of the blade at the tip of the pile, etc. There is no difference in the pile tip conditions due to the shape of the blades, and stable settlement characteristics can be obtained.

一方、本発明の請求項７に記載の基礎構造の施工方法は、杭基礎と直接基礎とを併用して上部構造を支持する基礎構造の施工方法であって、鋼管杭を回転させて地盤に貫入し、地盤貫入時のトルク値に基づいて杭先端が支持層に到達したことを確認する支持層確認手順と、前記支持層確認手順の後に、貫入方向と逆方向に回転して所定量だけ上方に引き上げ、杭先端地盤を緩める杭先端地盤弛緩手順と、前記地盤貫入後の鋼管杭の杭頭部に連結して地盤上に底版部を形成する直接基礎形成手順とを備え、前記鋼管杭および底版部の上側に構築される上部構造の荷重で前記鋼管杭が所定量だけ沈下することで、この沈下した鋼管杭による支持力と、この鋼管杭に伴って沈下する前記底版部による支持力と、の両方の支持力によって前記上部構造の荷重が支持されることを特徴とする。   On the other hand, the construction method of the foundation structure according to claim 7 of the present invention is a construction method of the foundation structure that supports the upper structure using the pile foundation and the direct foundation in combination, and rotates the steel pipe pile to the ground. After the intrusion, the support layer confirmation procedure for confirming that the pile tip has reached the support layer based on the torque value at the time of the ground penetration, and after the support layer confirmation procedure, it rotates in the direction opposite to the penetration direction and only a predetermined amount The steel pipe pile comprises: a pile tip ground loosening procedure for lifting upward and loosening the pile tip ground; and a direct foundation forming procedure for forming a bottom slab portion on the ground by connecting to the pile head of the steel pipe pile after the ground penetration. When the steel pipe pile sinks by a predetermined amount due to the load of the superstructure built on the upper side of the bottom slab part, the support force by the subsidized steel pipe pile and the support force by the bottom slab part that sinks along with the steel pipe pile And the superstructure by both supporting force Characterized in that the load is supported.

さらに、本発明の請求項８に記載の基礎構造の施工方法は、杭基礎と直接基礎とを併用して上部構造を支持する基礎構造の施工方法であって、杭先端に螺旋状あるいは複数の板からなる羽根を有した鋼管杭を回転させて地盤に貫入し、地盤貫入時のトルク値に基づいて杭先端が支持層に到達したことを確認する支持層確認手順と、前記支持層確認手順後に、杭先端の深さ位置を維持したままで貫入方向および逆方向の少なくとも一方に回転し、杭先端地盤を緩める杭先端地盤弛緩手順と、前記地盤貫入後の鋼管杭の杭頭部に連結して地盤上に底版部を形成する直接基礎形成手順とを備え、前記鋼管杭および底版部の上側に構築される上部構造の荷重で前記鋼管杭が所定量だけ沈下することで、この沈下した鋼管杭による支持力と、この鋼管杭に伴って沈下する前記底版部による支持力と、の両方の支持力によって前記上部構造の荷重が支持されることを特徴とする。   Furthermore, the construction method of the foundation structure according to claim 8 of the present invention is a construction method of the foundation structure that supports the upper structure by using the pile foundation and the direct foundation together, and the pile tip has a spiral shape or a plurality of methods. A support layer confirmation procedure for rotating a steel pipe pile having blades made of plates and penetrating into the ground and confirming that the tip of the pile has reached the support layer based on the torque value at the time of ground penetration, and the support layer confirmation procedure Later, while maintaining the depth position of the pile tip, rotate to at least one of the penetration direction and the reverse direction, loosen the pile tip ground, and connect to the pile head of the steel pipe pile after the ground penetration And a direct foundation forming procedure for forming a bottom slab portion on the ground, and the steel pipe pile is sunk by a predetermined amount due to the load of the steel pipe pile and the upper structure constructed above the bottom slab portion. Bearing capacity of steel pipe pile and this steel pipe pile With the load of the upper structure by the supporting force of the both, the support force by said bottom plate section for subsidence in is characterized in that it is supported.

以上の施工方法によれば、前述した基礎構造と同様に、杭先端の支持力を十分に確保し、かつ直接基礎の支持力も得られるので、基礎構造全体の支持力を高めることができ、コスト低減を図りつつ、大規模な建物にも適用することが可能になる。さらに、軟弱な地盤に対しても適用可能となり、杭基礎および直接基礎の併用基礎構造の適用範囲を拡大することができる。また、逆回転によって鋼管杭を上方に引き上げるか、あるいは螺旋状あるいは複数の板からなる羽根を同一深さ位置で空回りさせることで、容易に杭先端近傍の地盤を緩めることができる。   According to the construction method described above, as in the case of the foundation structure described above, the support force of the pile tip can be sufficiently secured and the support force of the foundation can be obtained directly. It can be applied to a large-scale building while reducing. Furthermore, it can be applied to soft ground, and the application range of the combined foundation structure of pile foundation and direct foundation can be expanded. Further, the ground near the tip of the pile can be easily loosened by pulling the steel pipe pile upward by reverse rotation, or by rotating the blades made of a spiral or a plurality of plates at the same depth position.

さらに、本発明の請求項９に記載の基礎構造の施工方法は、請求項７または請求項８に記載の基礎構造の施工方法において、前記杭先端地盤弛緩手順の後に、緩めた杭先端近傍の地盤にセメントミルクを注入して根固めする根固め手順を備えたことを特徴とする。
このような構成によれば、前述と同様に、緩めた杭先端近傍の地盤を根固めすることで、杭先端の羽根形状による沈下性状のばらつきをなくして、安定した沈下性状を得ることができる。 Furthermore, the construction method of the foundation structure according to claim 9 of the present invention is the construction method of the foundation structure according to claim 7 or claim 8, wherein after the pile tip ground relaxation procedure, It is characterized by having a rooting procedure in which cement milk is poured into the ground and solidified.
According to such a configuration, as described above, by stabilizing the ground in the vicinity of the loose pile tip, it is possible to eliminate the variation in the settlement property due to the blade shape of the pile tip and obtain a stable settlement property. .

以上のような本発明の基礎構造および基礎構造の施工方法によれば、支持力を十分に確保してコスト低減を図ることが可能で、地盤の硬軟に関わらずに適用範囲を拡大することができる。   According to the foundation structure and the foundation structure construction method of the present invention as described above, it is possible to reduce the cost by sufficiently securing the supporting force, and it is possible to expand the application range regardless of the hardness of the ground. it can.

以下、本発明の実施形態を図面に基づいて説明する。
図１は、本発明の実施形態に係る基礎構造を備えた建物１を示す断面図である。図２(Ａ)〜(Ｄ)は、建物１の基礎構造における鋼管杭２の施工手順を説明する図である。
図１において、建物１は、地盤Ｇに貫入される複数の鋼管杭（杭体）２からなる杭基礎と、地盤Ｇ上に形成される底版部である耐圧版３からなる直接基礎と、を併用して上部構造４を支持する基礎構造を備えている。
耐圧版３は、鋼管杭２を地盤Ｇに貫入した後に地表面を掘削してから、フーチング（パイルキャップ）５を介して鋼管杭２の杭頭部と連結（一体化）される鉄筋コンクリート造のスラブである。そして、耐圧版３は、下方からの地盤Ｇの地反力を受けることで、上部構造４の荷重を地盤Ｇに伝達できるようになっている。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a building 1 having a foundation structure according to an embodiment of the present invention. 2A to 2D are diagrams for explaining the construction procedure of the steel pipe pile 2 in the foundation structure of the building 1.
In FIG. 1, a building 1 includes a pile foundation composed of a plurality of steel pipe piles (pile bodies) 2 penetrating into the ground G, and a direct foundation composed of a pressure plate 3 that is a bottom slab formed on the ground G. The base structure which supports the upper structure 4 in combination is provided.
The pressure plate 3 is made of a reinforced concrete structure in which the steel pipe pile 2 is penetrated into the ground G and then the ground surface is excavated, and then connected (integrated) with the pile head of the steel pipe pile 2 via a footing (pile cap) 5. It is a slab. And the pressure-resistant plate 3 can transmit the load of the upper structure 4 to the ground G by receiving the ground reaction force of the ground G from below.

鋼管杭２は、円形鋼管で形成された鋼管杭本体２Ａと、この鋼管杭本体２Ａの先端（下端）に固定された螺旋状の羽根２Ｂとを有して形成されている。そして、鋼管杭１は、図２に示すように、杭打ち機Ｍの回転圧入装置Ｃにより回転されて羽根２Ｂが地盤Ｇにねじ込まれて地盤Ｇに貫入される。
すなわち、図２(Ａ)に示すように、杭打ち機Ｍによって鋼管杭２を建て込み、図２(Ｂ)に示すように、鋼管杭１を垂直にして杭芯位置にセットする。
次に、図２(Ｃ)、図２(Ｄ)に示すように、回転圧入装置Ｃを回転させて羽根２Ｂを地盤Ｇにねじ込むことで鋼管杭２を地盤Ｇに貫入する（回転圧入手順）。
なお、図２においては、鋼管杭２が上下に連結されていない場合を図示したが、この鋼管杭２を下杭とし、その上に上杭を溶接して一体化してもよく、さらには３本以上の鋼管杭２を連結して下杭、中杭、上杭を一体化してもよく、その場合でも施工方法としては略同様の手順を繰り返すこととなる。また、杭打ち機Ｍとしては、図示するもの以外に胴体把持型の全旋回型ケーシングジャッキ等を用いることもできる。 The steel pipe pile 2 has a steel pipe pile main body 2A formed of a circular steel pipe and a spiral blade 2B fixed to the tip (lower end) of the steel pipe pile main body 2A. As shown in FIG. 2, the steel pipe pile 1 is rotated by the rotary press-fitting device C of the pile driving machine M, and the blade 2 </ b> B is screwed into the ground G and penetrates into the ground G.
That is, as shown in FIG. 2 (A), the steel pipe pile 2 is built by the pile driving machine M, and as shown in FIG. 2 (B), the steel pipe pile 1 is set vertically to the pile core position.
Next, as shown in FIGS. 2C and 2D, the steel pipe pile 2 is penetrated into the ground G by rotating the rotary press-fitting device C and screwing the blades 2B into the ground G (rotational press-fitting procedure). .
In addition, although the case where the steel pipe pile 2 was not connected up and down was illustrated in FIG. 2, this steel pipe pile 2 may be used as a lower pile, and an upper pile may be welded and integrated on it. More than this steel pipe pile 2 may be connected and a lower pile, a middle pile, and an upper pile may be integrated, and even in that case, as a construction method, a substantially similar procedure will be repeated. Further, as the pile driving machine M, a torso gripping type fully swiveling casing jack or the like can be used in addition to the illustrated one.

以上の回転圧入手順において、杭打ち機Ｍの回転圧入装置Ｃには、回転圧入の際に鋼管杭２に作用する回転トルク値を測定する測定機が設けられており、このトルク値を管理することで、鋼管杭２の先端が地盤Ｇ中の中間層Ｇ１（図３）にあるか、あるいは支持層Ｇ２に到達したか否かが判断できるようになっている。すなわち、鋼管杭２に作用するトルク値は、地盤ＧのＮ値に応じて変動することが知られており、Ｎ値が大きくなる支持層Ｇ２に鋼管杭２の先端が到達すると、トルク値が急激に上昇することから支持層Ｇ２に到達したことが判断できるようになっている（支持層確認手順）。   In the rotational press-fitting procedure described above, the rotary press-fitting device C of the pile driving machine M is provided with a measuring machine that measures the rotational torque value acting on the steel pipe pile 2 during the rotary press-fitting, and manages this torque value. Thus, it can be determined whether the tip of the steel pipe pile 2 is in the intermediate layer G1 (FIG. 3) in the ground G or has reached the support layer G2. That is, it is known that the torque value acting on the steel pipe pile 2 varies according to the N value of the ground G. When the tip of the steel pipe pile 2 reaches the support layer G2 where the N value increases, the torque value is Since it rises rapidly, it can be judged that the support layer G2 has been reached (support layer confirmation procedure).

以下、支持層確認手順の後に実施する杭先端地盤弛緩手順に関して、図３に基づいて第１実施形態を説明し、図４〜図６に基づいて第２実施形態を説明し、杭先端地盤弛緩手順の後に実施する根固め手順に関して、図７、図８に基づいて第３実施形態を説明する。
なお、各実施形態以降において、次の第１実施形態で説明する構成部材と同じ構成部材、および同様な機能を有する構成部材には、第１実施形態の構成部材と同じ符号を付し、それらの説明を省略または簡略化する。 Hereinafter, regarding the pile tip ground relaxation procedure performed after the support layer confirmation procedure, the first embodiment will be described based on FIG. 3, the second embodiment will be described based on FIGS. 4 to 6, and the pile tip ground relaxation. A third embodiment will be described with reference to FIGS. 7 and 8 regarding a consolidation procedure performed after the procedure.
In the following embodiments, the same constituent members as those described in the first embodiment and the constituent members having the same functions are denoted by the same reference numerals as those in the first embodiment. The description of is omitted or simplified.

〔第１実施形態〕
図３は、第１実施形態に係る基礎構造の施工方法を示す断面図である。
前述の支持層確認手順において、鋼管杭２の先端が支持層Ｇ２に到達したことを確認した後に、杭打ち機Ｍの回転圧入装置Ｃによって、さらに鋼管杭２を回転圧入して所定深さ（例えば、鋼管杭本体２Ａの直径寸法分）だけ支持層Ｇ２に杭先端を貫入する。
次に、貫入した杭先端の位置を維持した状態で鋼管杭２を貫入方向および逆方向の一方または交互に回転する。この回転により羽根２Ｂが一定深さ位置で空回りすることで、鋼管杭２の杭先端近傍の地盤Ｇ２Ａが緩められる（杭先端地盤弛緩手順）。 [First Embodiment]
Drawing 3 is a sectional view showing the construction method of the foundation structure concerning a 1st embodiment.
In the above-mentioned support layer confirmation procedure, after confirming that the tip of the steel pipe pile 2 has reached the support layer G2, the steel pipe pile 2 is further rotationally press-fitted by the rotary press-fitting device C of the pile driving machine M to obtain a predetermined depth ( For example, the pile tip is penetrated into the support layer G2 by the diameter of the steel pipe pile main body 2A).
Next, the steel pipe pile 2 is rotated in one of the penetration direction and the reverse direction or alternately in a state in which the position of the penetrated pile tip is maintained. This rotation causes the blade 2B to idle at a certain depth position, thereby loosening the ground G2A in the vicinity of the pile tip of the steel pipe pile 2 (pile tip ground loosening procedure).

以上のようにして複数の鋼管杭２を地盤に貫入した後に、図１に示すフーチング５を鋼管杭２の杭頭部に固定して構築するとともに、フーチング５と一体に耐圧版３を地盤Ｇ上に構築して鋼管杭２に連結する（直接基礎形成手順）。
さらに、鋼管杭２、フーチング５および耐圧版３の上側に上部構造４を順次構築し、この上部構造４の荷重がフーチング５を介して鋼管杭２に作用するのに従って、緩められた地盤Ｇ２Ａの高さ寸法に応じて鋼管杭２が沈下する。この鋼管杭２の沈下に伴って緩められた地盤Ｇ２Ａが徐々に締め固められ、沈下量に応じて杭先端の支持力ＲP1が発揮され、鋼管杭本体２Ａ周面摩擦による支持力ＲP2と併せて鋼管杭２の支持力（ＲP1＋ＲP2）が発揮される。 After the plurality of steel pipe piles 2 have penetrated into the ground as described above, the footing 5 shown in FIG. 1 is fixed to the pile head of the steel pipe pile 2, and the pressure plate 3 is integrated with the footing 5 in the ground G. It is constructed above and connected to the steel pipe pile 2 (direct foundation forming procedure).
Further, the upper structure 4 is sequentially constructed on the upper side of the steel pipe pile 2, the footing 5 and the pressure plate 3, and the load of the upper structure 4 acts on the steel pipe pile 2 through the footing 5 to loosen the ground G2A. The steel pipe pile 2 sinks according to the height dimension. The ground G2A loosened with the settlement of the steel pipe pile 2 is gradually compacted, and the supporting force RP1 at the tip of the pile is exhibited according to the amount of settlement, along with the supporting force RP2 due to the peripheral friction of the steel pipe pile body 2A. The bearing capacity (RP1 + RP2) of the steel pipe pile 2 is exhibited.

そして、鋼管杭２の沈下に伴ってフーチング５、耐圧版３および上部構造４も沈下し、耐圧版３の沈下に伴ってその底面の地盤Ｇが徐々に締め固められ、沈下量に応じて地反力による支持力ＲS が発揮される。
以上の鋼管杭２の支持力（ＲP1＋ＲP2）および耐圧版３底面の支持力ＲS と、上部構造４を含めた建物１全体の荷重とが釣り合う位置まで沈下した後に、沈下が止まる。これにより、鋼管杭２および耐圧版３の両方の支持力（ＲP1＋ＲP2＋ＲS ）、すなわち杭基礎および直接基礎の両者によって上部構造４の荷重が支持されることになる。 As the steel pipe pile 2 sinks, the footing 5, the pressure plate 3 and the upper structure 4 also sink, and as the pressure plate 3 sinks, the ground G on the bottom surface is gradually compacted, depending on the amount of settlement. Support force RS due to reaction force is exhibited.
After sinking to a position where the support force (RP1 + RP2) of the steel pipe pile 2 and the support force RS of the bottom face of the pressure plate 3 balance with the load of the entire building 1 including the upper structure 4, the settlement stops. As a result, the load of the superstructure 4 is supported by the supporting force (RP1 + RP2 + RS) of both the steel pipe pile 2 and the pressure plate 3, that is, both the pile foundation and the direct foundation.

このような本実施形態によれば、以下のような効果がある。
（１）すなわち、鋼管杭２の杭先端が支持層Ｇ２に到達したことを確認してから杭先端近傍の地盤Ｇ２Ａを緩めておき、その後に上部構造４の荷重が加わることで緩めた分だけ鋼管杭２が沈下して杭先端の支持力ＲP1が発揮されるとともに、鋼管杭２の沈下に伴って沈下する耐圧版３底面にも地反力が作用して支持力ＲS が得られ、これらの鋼管杭２および耐圧版３の両方の支持力（ＲP1＋ＲP2＋ＲS ）で上部構造４を支持することができる。従って、杭先端の支持力ＲP1を十分に確保し、かつ直接基礎の支持力ＲS も得られるので、基礎構造全体の支持力（ＲP1＋ＲP2＋ＲS ）を高めることができ、杭径や杭本数を増大させることなくコスト低減を図りつつ、規模の大きな建物１にも適用することが可能になる。 According to this embodiment, there are the following effects.
(1) That is, after confirming that the pile tip of the steel pipe pile 2 has reached the support layer G2, the ground G2A in the vicinity of the pile tip is loosened, and then the amount loosened by applying the load of the upper structure 4 The steel pipe pile 2 sinks and the support force RP1 at the tip of the pile is exerted, and the ground reaction force acts on the bottom surface of the pressure plate 3 that sinks as the steel pipe pile 2 sinks, resulting in the support force RS. The upper structure 4 can be supported by the supporting force (RP1 + RP2 + RS) of both the steel pipe pile 2 and the pressure plate 3. Therefore, sufficient support force RP1 at the tip of the pile can be secured sufficiently and the support force RS of the foundation can be obtained directly, so that the support force of the entire foundation structure (RP1 + RP2 + RS) can be increased, and the pile diameter and number of piles can be increased. Thus, the present invention can be applied to a large-scale building 1 while reducing costs.

（２）さらに、杭先端地盤Ｇ２Ａを予め緩めた分だけ鋼管杭２が沈下して支持力ＲP1が発揮されるので、この沈下した位置よりもさらに下方への鋼管杭２の沈下が生じにくく、かつ複数の鋼管杭２における沈下量が均等化できるため、表層地盤が軟弱な場合であっても不等沈下を防止することができる。従って、軟弱な地盤に対しても杭基礎および直接基礎併用の基礎構造が適用可能となり、その適用範囲を拡大することができる。 (2) Further, since the steel pipe pile 2 sinks by the amount of loosening the pile tip ground G2A in advance and the supporting force RP1 is exerted, the steel pipe pile 2 is less likely to sink further downward than the sinked position. And since the amount of settlement in a plurality of steel pipe piles 2 can be equalized, even if the surface layer ground is soft, uneven settlement can be prevented. Therefore, the pile foundation and the foundation structure combined with the direct foundation can be applied to the soft ground, and the application range can be expanded.

（３）また、鋼管杭２を回転圧入する杭打ち機Ｍの回転圧入装置Ｃによって鋼管杭２のトルク値を管理することで、杭先端が支持層Ｇ２に到達したことが容易かつ正確に判断でき、施工の迅速化および容易化を図ることができる。さらに、支持層Ｇ２に貫入させてから鋼管杭２の深さ位置を変えずに正回転や逆回転させることで、羽根２Ｂが同一深さ位置で空回りし、容易に杭先端近傍の地盤Ｇ２Ａを緩めることができる。 (3) In addition, by managing the torque value of the steel pipe pile 2 by the rotary press-fitting device C of the pile driving machine M that rotationally presses the steel pipe pile 2, it is easily and accurately determined that the pile tip has reached the support layer G2. The construction can be speeded up and facilitated. Furthermore, the blade 2B is idled at the same depth position without changing the depth position of the steel pipe pile 2 after penetrating into the support layer G2, so that the ground G2A near the tip of the pile can be easily rotated. Can be loosened.

〔第２実施形態〕
図４(Ａ)，(Ｂ)、および図５(Ａ)，(Ｂ)は、それぞれ第２実施形態に係る基礎構造の施工方法を示す断面図である。
本実施形態では、前述の支持層確認手順において、鋼管杭２の先端が支持層Ｇ２に到達したことを確認した後に、図４(Ａ)に示すように、杭打ち機Ｍの回転圧入装置Ｃによって、さらに鋼管杭２を回転して所定深さだけ支持層Ｇ２に杭先端を貫入する。
次に、杭先端を所定深さだけ支持層Ｇ２に貫入した位置から、回転圧入装置Ｃを逆方向に回転して、図４(Ｂ)示す位置まで、鋼管杭２を上方に引き上げる。このように鋼管杭２を引き上げることで、鋼管杭２の杭先端近傍における引き上げた高さ寸法分の地盤Ｇ２Ｂが緩められる（杭先端地盤弛緩手順）。そして、引き上げた後の鋼管杭２の杭先端位置が支持層Ｇ２上面よりも下方に位置するようになっている。
一方、図５においては、図５(Ａ)に示すように、鋼管杭２の先端が支持層Ｇ２に到達したことを確認した後に、杭先端を支持層Ｇ２に貫入することなく回転圧入装置Ｃを逆方向に回転して、図５(Ｂ)に示す位置まで鋼管杭２を上方に引き上げる。すなわち、引き上げた後の鋼管杭２の杭先端位置が支持層Ｇ２上面よりも上方に位置するようになっている。 [Second Embodiment]
FIGS. 4A and 4B and FIGS. 5A and 5B are cross-sectional views showing a construction method of the foundation structure according to the second embodiment, respectively.
In this embodiment, after confirming that the tip of the steel pipe pile 2 has reached the support layer G2 in the above-described support layer confirmation procedure, as shown in FIG. 4 (A), the rotary press-fitting device C of the pile driving machine M is used. Thus, the steel pipe pile 2 is further rotated to penetrate the pile tip into the support layer G2 by a predetermined depth.
Next, the steel pipe pile 2 is pulled up to the position shown in FIG. 4B by rotating the rotary press-fitting device C in the reverse direction from the position where the tip of the pile penetrates the support layer G2 by a predetermined depth. By pulling up the steel pipe pile 2 in this way, the ground G2B for the height dimension in the vicinity of the pile tip of the steel pipe pile 2 is loosened (pile tip ground loosening procedure). And the pile front-end | tip position of the steel pipe pile 2 after raising is located below the support layer G2 upper surface.
On the other hand, in FIG. 5, after confirming that the tip of the steel pipe pile 2 has reached the support layer G2, as shown in FIG. 5 (A), the rotary press-fitting device C without penetrating the pile tip into the support layer G2. Is rotated in the reverse direction and the steel pipe pile 2 is pulled up to the position shown in FIG. 5 (B). That is, the pile tip position of the steel pipe pile 2 after being pulled up is positioned above the upper surface of the support layer G2.

以上のようにして複数の鋼管杭２を地盤に貫入した後の手順に関しては、前記第１実施形態の手順と略同様であるため、説明を省略する。
そして、図５に示したように、支持層Ｇ２上面よりも上方に位置するよう杭先端を位置させる場合であっても、前述の支持層確認手順にて支持層Ｇ２まで鋼管杭２の先端が到達したことを確認してから引き上げることで、図６に示すように、支持層Ｇ２上面に不陸があって深さ位置がばらつく、あるいは支持層Ｇ２上面が傾斜したような場合であっても、杭先端と支持層Ｇ２の上面との距離を一定にすることができるようになっている。これにより、鋼管杭２を引き上げることで緩められる地盤Ｇ２Ｂの強度や剛性を均質化させることができ、上部構造４の荷重による沈下量や、沈下後に発揮される先端支持力ＲP1を安定化させることができる。 Since the procedure after penetrating the plurality of steel pipe piles 2 into the ground as described above is substantially the same as the procedure of the first embodiment, description thereof will be omitted.
And as shown in FIG. 5, even if it is a case where a pile front-end | tip is located so that it may be located above the support layer G2 upper surface, the front-end | tip of the steel pipe pile 2 is carried out to the support layer G2 in the above-mentioned support layer confirmation procedure. Even if the upper surface of the support layer G2 is uneven and the depth position varies, or the upper surface of the support layer G2 is inclined, as shown in FIG. The distance between the tip of the pile and the upper surface of the support layer G2 can be made constant. This makes it possible to homogenize the strength and rigidity of the ground G2B, which is loosened by pulling up the steel pipe pile 2, and stabilize the amount of settlement due to the load of the upper structure 4 and the tip support force RP1 exhibited after the settlement. Can do.

このような本実施形態によれば、前述の（１）、（２）と略同様の効果に加えて、以下のような効果がある。
（４）すなわち、鋼管杭２を回転圧入する杭打ち機Ｍの回転圧入装置Ｃによって鋼管杭２のトルク値を管理することで、杭先端が支持層Ｇ２に到達したことが容易かつ正確に判断でき、施工の迅速化および容易化を図ることができる。さらに、支持層Ｇ２に貫入させるか支持層Ｇ２を確認してから、鋼管杭２を逆回転さて引き上げることで、容易に杭先端近傍の地盤Ｇ２Ｂを緩めることができる。 According to the present embodiment, in addition to the effects substantially similar to the above (1) and (2), there are the following effects.
(4) That is, by managing the torque value of the steel pipe pile 2 by the rotary press-fitting device C of the pile driving machine M that rotationally presses the steel pipe pile 2, it is easily and accurately determined that the pile tip has reached the support layer G2. The construction can be speeded up and facilitated. Furthermore, after confirming the support layer G2 or penetrating the support layer G2, the ground G2B in the vicinity of the tip of the pile can be easily loosened by pulling the steel pipe pile 2 by reverse rotation.

〔第３実施形態〕
図７(Ａ)，(Ｂ)は、第３実施形態に係る基礎構造における鋼管杭２を示す側面図および底面図である。図８は、施工後の鋼管杭２を示す断面図である。
本実施形態の鋼管杭２において、鋼管杭本体２Ａ内部には、根固め材であるセメントミルク注入用の管２Ｃが羽根２Ｂ底面に開口して配設されている。そして、この管２Ｃは、鋼管杭２の杭頭よりも上方の地上まで連続して設けられており、鋼管杭２の地盤Ｇへの貫入後に、地上から管２Ｃを通して杭先端地盤にセメントミルクを注入することができるようになっている。
以上の鋼管杭２を用いた本実施形態では、前述の第１実施形態または第２実施形態の杭先端地盤弛緩手順において、鋼管杭２の杭先端地盤Ｇ２Ａ，Ｇ２Ｂを緩めた後に、管２Ｃよりセメントミルクを吐出しながら鋼管杭２を回転させてセメントミルクを羽根２Ｂの周辺に充填し、充填したセメントミルクが固化することで杭先端部に根固め部２Ｄを形成する（根固め手順）。
なお、根固め部２Ｄは、支持層Ｇ２の上面よりも下側に形成されてもよく、また支持層Ｇ２の上面よりも上側に形成されてもよく、さらには支持層Ｇ２の上面近傍に形成されてもよい。 [Third Embodiment]
7A and 7B are a side view and a bottom view showing the steel pipe pile 2 in the foundation structure according to the third embodiment. FIG. 8 is a cross-sectional view showing the steel pipe pile 2 after construction.
In the steel pipe pile 2 of this embodiment, a pipe 2C for cement milk injection, which is a root hardening material, is disposed in the steel pipe pile main body 2A so as to open to the bottom surface of the blade 2B. And this pipe 2C is continuously provided to the ground above the pile head of the steel pipe pile 2, and after penetration of the steel pipe pile 2 into the ground G, cement milk is applied to the pile tip ground from the ground through the pipe 2C. It can be injected.
In this embodiment using the steel pipe pile 2 described above, after loosening the pile tip ground G2A, G2B of the steel pipe pile 2 in the pile tip ground loosening procedure of the first embodiment or the second embodiment described above, the pipe 2C The steel pipe pile 2 is rotated while discharging the cement milk so that the cement milk is filled around the blades 2B, and the filled cement milk is solidified to form a rooted portion 2D at the tip of the pile (root consolidation procedure).
The root hardening portion 2D may be formed below the upper surface of the support layer G2, may be formed above the upper surface of the support layer G2, and further formed near the upper surface of the support layer G2. May be.

このような本実施形態によれば、前述の各効果に加えて、以下のような効果がある。
（５）すなわち、緩めた杭先端近傍の地盤をセメントミルクで根固めすることで、杭先端の羽根２Ｂ形状による沈下性状のばらつきをなくして、安定した沈下性状を得ることができる。 According to the present embodiment, in addition to the above-described effects, the following effects can be obtained.
(5) That is, by stabilizing the loose ground near the tip of the pile with cement milk, variations in the settling property due to the blade 2B shape at the tip of the pile can be eliminated, and a stable settling property can be obtained.

なお、本発明は、前記実施形態に限定されるものではなく、本発明の目的を達成できる他の構成等を含み、以下に示すような変形等も本発明に含まれる。
例えば、前記実施形態においては、杭体として鋼管杭２を用い、この鋼管杭２を回転圧入により地盤Ｇに貫入する工法を採用したが、杭基礎としては場所打ちコンクリート杭でもよく、またＰＣ杭を埋込み工法や打込み工法等で地盤Ｇに貫入させるものでもよい。この際、杭先端地盤を緩める方法としては、水流や空気圧による方法や、弾性材、弾塑性材等の先端地盤よりも剛性が小さく上部構造の荷重によって変形する部材を杭体と杭先端地盤との間に介挿する方法などが採用可能である。 In addition, this invention is not limited to the said embodiment, Including other structures etc. which can achieve the objective of this invention, the deformation | transformation etc. which are shown below are also contained in this invention.
For example, in the said embodiment, although the steel pipe pile 2 was used as a pile body, and the construction method which penetrates this steel pipe pile 2 to the ground G by rotary press fit, a cast-in-place concrete pile may be used as a pile foundation, and PC pile May be inserted into the ground G by an embedding method or a driving method. At this time, as a method of loosening the pile tip ground, there is a method using water flow or air pressure, or a member that is less rigid than the tip ground such as an elastic material, elastic-plastic material, etc. It is possible to adopt a method of interposing between the two.

その他、本発明を実施するための最良の構成、方法などは、以上の記載で開示されているが、本発明は、これに限定されるものではない。すなわち、本発明は、主に特定の実施形態に関して特に図示され、かつ説明されているが、本発明の技術的思想および目的の範囲から逸脱することなく、以上述べた実施形態に対し、形状、材質、数量、その他の詳細な構成において、当業者が様々な変形を加えることができるものである。
従って、上記に開示した形状、材質などを限定した記載は、本発明の理解を容易にするために例示的に記載したものであり、本発明を限定するものではないから、それらの形状、材質などの限定の一部もしくは全部の限定を外した部材の名称での記載は、本発明に含まれるものである。 In addition, the best configuration, method and the like for carrying out the present invention have been disclosed in the above description, but the present invention is not limited to this. That is, the invention has been illustrated and described with particular reference to certain specific embodiments, but without departing from the spirit and scope of the invention, Various modifications can be made by those skilled in the art in terms of material, quantity, and other detailed configurations.
Therefore, the description limiting the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such restrictions is included in this invention.

本発明の実施形態に係る基礎構造を備えた建物を示す断面図である。It is sectional drawing which shows the building provided with the foundation structure which concerns on embodiment of this invention. (Ａ)〜(Ｄ)は、前記基礎構造における杭の施工手順を説明する図である。(A)-(D) is a figure explaining the construction procedure of the pile in the said foundation structure. 第１実施形態に係る基礎構造の施工方法を示す断面図である。It is sectional drawing which shows the construction method of the foundation structure which concerns on 1st Embodiment. (Ａ)，(Ｂ)は、第２実施形態に係る基礎構造の施工方法を示す断面図である。(A), (B) is sectional drawing which shows the construction method of the foundation structure which concerns on 2nd Embodiment. (Ａ)，(Ｂ)は、第２実施形態に係る基礎構造の施工方法を示す断面図である。(A), (B) is sectional drawing which shows the construction method of the foundation structure which concerns on 2nd Embodiment. 前記基礎構造を示す断面図である。It is sectional drawing which shows the said basic structure. (Ａ)，(Ｂ)は、第３実施形態に係る基礎構造における杭を示す側面図および底面図である。(A), (B) is the side view and bottom view which show the pile in the foundation structure which concerns on 3rd Embodiment. 第３実施形態の施工後の杭を示す断面図である。It is sectional drawing which shows the pile after construction of 3rd Embodiment.

符号の説明Explanation of symbols

２…杭体である鋼管杭、２Ｂ…羽根、３…底版部である耐圧版、４…上部構造、Ｇ…地盤、Ｇ２…支持層。   2 ... Steel pipe pile which is a pile body, 2B ... Blade, 3 ... Pressure-resistant plate which is bottom plate part, 4 ... Superstructure, G ... Ground, G2 ... Support layer.

Claims (9)

杭基礎と直接基礎とを併用して上部構造を支持する基礎構造であって、
地盤に貫入される杭体と、地盤貫入後の杭体の杭頭部に連結されて地盤上に形成される底版部とを備え、
前記杭体の杭先端が支持層に到達したことを確認してから当該杭先端近傍の地盤を緩めておき、上部構造の荷重により所定量だけ沈下することで発揮される前記杭体による支持力と、この杭体に伴って沈下することで地反力を受けて発揮される前記底版部による支持力と、の両方の支持力によって前記上部構造の荷重を支持することを特徴とする基礎構造。 A foundation structure that supports the superstructure using a pile foundation and a direct foundation together,
A pile body penetrating into the ground, and a bottom plate portion formed on the ground connected to the pile head of the pile body after penetrating the ground,
After confirming that the pile tip of the pile body has reached the support layer, loosen the ground near the pile tip, and support force by the pile body exerted by sinking a predetermined amount due to the load of the superstructure And the supporting force by the bottom plate part that is exerted by receiving a ground reaction force by sinking along with the pile body, and supporting the load of the upper structure by both supporting forces . 請求項１に記載の基礎構造において、
前記杭体は、回転により地盤に貫入される鋼管杭であって、
この鋼管杭は、地盤貫入時のトルク値に基づいて杭先端が支持層に到達したことが確認された後に、貫入方向と逆方向に回転されて所定量だけ上方に引き上げられ、
前記鋼管杭を引き上げることによって杭先端近傍の地盤が緩められることを特徴とする基礎構造。 The basic structure according to claim 1,
The pile body is a steel pipe pile that penetrates into the ground by rotation,
After confirming that the pile tip has reached the support layer based on the torque value at the time of ground penetration, this steel pipe pile is rotated in the direction opposite to the penetration direction and pulled upward by a predetermined amount,
A foundation structure characterized in that the ground near the tip of the pile is loosened by pulling up the steel pipe pile. 請求項２に記載の基礎構造において、
前記引き上げた後の鋼管杭の杭先端が前記支持層上面よりも上方に位置することを特徴とする基礎構造。 In the basic structure according to claim 2,
The foundation structure characterized by the pile front-end | tip of the steel pipe pile after the said raising being located above the said support layer upper surface. 請求項２に記載の基礎構造において、
前記鋼管杭は、杭先端が所定深さだけ支持層に貫入された後に引き上げられ、前記引き上げた後の鋼管杭の杭先端が前記支持層上面よりも下方に位置することを特徴とする基礎構造。 In the basic structure according to claim 2,
The steel pipe pile is pulled up after the pile tip has penetrated into the support layer by a predetermined depth, and the pile tip of the steel pipe pile after the lift is located below the upper surface of the support layer. . 請求項１に記載の基礎構造において、
前記杭体は、杭先端に螺旋状あるいは複数の板からなる羽根を有して回転により地盤に貫入される鋼管杭であって、
この鋼管杭は、地盤貫入時のトルク値に基づいて杭先端が支持層に到達したことが確認されるとともに、支持層確認後に、杭先端の深さ位置を維持したままで貫入方向および逆方向の少なくとも一方に回転され、
前記鋼管杭の回転によって杭先端近傍の地盤が緩められることを特徴とする基礎構造。 The basic structure according to claim 1,
The pile body is a steel pipe pile that has a blade made of a spiral or a plurality of plates at the tip of the pile and penetrates into the ground by rotation,
This steel pipe pile is confirmed that the pile tip has reached the support layer based on the torque value at the time of penetration into the ground, and after confirming the support layer, the penetration direction and the reverse direction are maintained while maintaining the depth position of the pile tip Rotated to at least one of
A foundation structure characterized in that the ground near the tip of the pile is loosened by the rotation of the steel pipe pile. 請求項１から請求項５のいずれかに記載の基礎構造において、
前記緩めた杭先端近傍の地盤が根固めされることを特徴とする基礎構造。 In the foundation structure according to any one of claims 1 to 5,
A foundation structure characterized in that the ground in the vicinity of the loosened pile tip is solidified. 杭基礎と直接基礎とを併用して上部構造を支持する基礎構造の施工方法であって、
鋼管杭を回転させて地盤に貫入し、地盤貫入時のトルク値に基づいて杭先端が支持層に到達したことを確認する支持層確認手順と、
前記支持層確認手順の後に、貫入方向と逆方向に回転して所定量だけ上方に引き上げ、杭先端地盤を緩める杭先端地盤弛緩手順と、
前記地盤貫入後の鋼管杭の杭頭部に連結して地盤上に底版部を形成する直接基礎形成手順とを備え、
前記鋼管杭および底版部の上側に構築される上部構造の荷重で前記鋼管杭が所定量だけ沈下することで、この沈下した鋼管杭による支持力と、この鋼管杭に伴って沈下する前記底版部による支持力と、の両方の支持力によって前記上部構造の荷重が支持されることを特徴とする基礎構造の施工方法。 It is a construction method of a foundation structure that supports a superstructure using a pile foundation and a direct foundation together,
Support layer confirmation procedure to rotate the steel pipe pile and penetrate into the ground, confirm that the pile tip has reached the support layer based on the torque value at the time of ground penetration,
After the support layer confirmation procedure, the pile tip ground loosening procedure of rotating in the opposite direction to the penetration direction and pulling up by a predetermined amount to loosen the pile tip ground,
Direct foundation formation procedure to form a bottom slab part on the ground connected to the pile head of the steel pipe pile after the ground penetration,
The steel pipe pile sinks by a predetermined amount by the load of the upper structure constructed on the upper side of the steel pipe pile and the bottom slab part, so that the supporting force by the subtracted steel pipe pile and the bottom slab part that sinks with the steel pipe pile The construction method of the foundation structure, wherein the load of the superstructure is supported by both the supporting force by the supporting force. 杭基礎と直接基礎とを併用して上部構造を支持する基礎構造の施工方法であって、
杭先端に螺旋状あるいは複数の板からなる羽根を有した鋼管杭を回転させて地盤に貫入し、地盤貫入時のトルク値に基づいて杭先端が支持層に到達したことを確認する支持層確認手順と、
前記支持層確認手順の後に、杭先端の深さ位置を維持したままで貫入方向および逆方向の少なくとも一方に回転し、杭先端地盤を緩める杭先端地盤弛緩手順と、
前記地盤貫入後の鋼管杭の杭頭部に連結して地盤上に底版部を形成する直接基礎形成手順とを備え、
前記鋼管杭および底版部の上側に構築される上部構造の荷重で前記鋼管杭が所定量だけ沈下することで、この沈下した鋼管杭による支持力と、この鋼管杭に伴って沈下する前記底版部による支持力と、の両方の支持力によって前記上部構造の荷重が支持されることを特徴とする基礎構造の施工方法。 It is a construction method of a foundation structure that supports a superstructure using a pile foundation and a direct foundation together,
Check the support layer to check that the pile tip has reached the support layer based on the torque value at the time of ground penetration by rotating a steel pipe pile with a spiral or multiple plate blades at the tip of the pile and penetrating into the ground Procedure and
After the support layer confirmation procedure, while maintaining the depth position of the pile tip, rotate in at least one of the penetration direction and the reverse direction, loosen the pile tip ground, and a pile tip ground relaxation procedure,
Direct foundation formation procedure to form a bottom slab part on the ground connected to the pile head of the steel pipe pile after the ground penetration,
The steel pipe pile sinks by a predetermined amount by the load of the upper structure constructed on the upper side of the steel pipe pile and the bottom slab part, so that the supporting force by the subtracted steel pipe pile and the bottom slab part that sinks with the steel pipe pile The construction method of the foundation structure, wherein the load of the superstructure is supported by both the supporting force by the supporting force. 請求項７または請求項８に記載の基礎構造の施工方法において、
前記杭先端地盤弛緩手順の後に、緩めた杭先端近傍の地盤にセメントミルクを注入して根固めする根固め手順を備えたことを特徴とする基礎構造の施工方法。 In the construction method of the foundation structure according to claim 7 or claim 8,
A foundation construction method characterized by comprising a root-solidifying procedure in which cement milk is poured into the ground near the loose pile tip and then solidified after the pile tip ground-relaxing procedure.
JP2005305774A 2005-10-20 2005-10-20 Foundation structure and construction method of foundation structure Expired - Fee Related JP4713297B2 (en)

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WO2011155619A1 (en) * 2010-06-07 2011-12-15 Ｊｆｅスチール株式会社 Foundation pile group
CN102535263A (en) * 2012-02-14 2012-07-04 中铁十九局集团有限公司 Roadbed with pile-net composite structure and construction method thereof
CN103015447A (en) * 2013-01-05 2013-04-03 江苏省城市规划设计研究院 Piled raft foundation structure provided with column pier type pile cap structures
US20130272801A1 (en) * 2011-08-25 2013-10-17 Nippon Steel & Sumikin Engineering Co., Ltd. Steel pipe pile and steel pipe pile implementation method
CN103362037A (en) * 2013-08-02 2013-10-23 北京交通大学 Pile plate structure analytic calculating method taking foundation soil mass bearing function into consideration
JP2016188510A (en) * 2015-03-30 2016-11-04 有限会社丸高重量 Design method for soil improvement work

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CN105862907B (en) * 2016-06-04 2018-06-22 福建省新能海上风电研发中心有限公司 Circular combined super-large diameter offshore wind farm single-pile foundation and its construction technology

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JP2002212947A (en) * 2001-01-17 2002-07-31 Kanematsu Nnk Corp Steel pipe with bottom widened and construction method for steel pipe pile with bottom widened
JP2003050911A (en) * 2001-08-07 2003-02-21 Nippon Steel Corp Device and system for information processing, insurance setting method, storage medium, and program
JP2004068253A (en) * 2002-08-01 2004-03-04 Nippon Steel Corp Foundation structure of structure

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JPS5985028A (en) * 1982-11-05 1984-05-16 Yasuyuki Yoshida Steel pipe pile and laying work thereof
JPH11303070A (en) * 1998-04-24 1999-11-02 Asahi Kasei Kenzai Kk Execution method for steel pipe pile with nose blade
JP2002129584A (en) * 2000-10-24 2002-05-09 Shimizu Corp Foundation structure
JP2002212947A (en) * 2001-01-17 2002-07-31 Kanematsu Nnk Corp Steel pipe with bottom widened and construction method for steel pipe pile with bottom widened
JP2003050911A (en) * 2001-08-07 2003-02-21 Nippon Steel Corp Device and system for information processing, insurance setting method, storage medium, and program
JP2004068253A (en) * 2002-08-01 2004-03-04 Nippon Steel Corp Foundation structure of structure

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011155619A1 (en) * 2010-06-07 2011-12-15 Ｊｆｅスチール株式会社 Foundation pile group
US20130272801A1 (en) * 2011-08-25 2013-10-17 Nippon Steel & Sumikin Engineering Co., Ltd. Steel pipe pile and steel pipe pile implementation method
US9328475B2 (en) * 2011-08-25 2016-05-03 Nippon Steel & Sumikin Engineering Co., Ltd. Steel pipe pile and steel pipe pile implementation method
CN102535263A (en) * 2012-02-14 2012-07-04 中铁十九局集团有限公司 Roadbed with pile-net composite structure and construction method thereof
CN103015447A (en) * 2013-01-05 2013-04-03 江苏省城市规划设计研究院 Piled raft foundation structure provided with column pier type pile cap structures
CN103362037A (en) * 2013-08-02 2013-10-23 北京交通大学 Pile plate structure analytic calculating method taking foundation soil mass bearing function into consideration
CN103362037B (en) * 2013-08-02 2015-08-26 北京交通大学 Consider the pile slab structure Analytic Calculation Method of foundation soil body supporting role
JP2016188510A (en) * 2015-03-30 2016-11-04 有限会社丸高重量 Design method for soil improvement work

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